Furnace pallets



2 Sheets-Sheet 1 Nw Q R. N S [3 m m w Q O R VB. m 1 I N J T r M w ww F aQ N M m l \v w H- I M M. km I Oct. 11, 1960 Filed Sept. 30. 195 7 Oct.11, 1960 F. J. BORON 2,955,812

FURNACE PALLETS Filed Sept. 30, 1957 2 Sheets-Sheet 2 m M /25 75 M /07 mr u A 1 (lV INVENTOR. FRANK J. B ORON BY h/wZwM/W ATTORNEYS UnitedStates Patent FURNACE PALLETS Frank J. Boron, Elyria, Ohio, assignor toAmerican Brake Shoe Company, New York, N.Y., a corporation of DelawareFiled Sept. 30, 1957, Ser. No. 686,939 3 Claims. (Cl. 2266-21) Thisinvention relatesto a pallet of a kind for moving ore material through afurnace area.

It is common practice in processing ore material such as iron or thelike to sinter the material in a furnace. Thus, ore material in arelatively finely divided state is moved through the furnace so as to befired therein, and during firing the material is sintered so as to beagglomerated into larger size cakes. In the instance of iron ore, thelarge cakes are the source of iron ore for blast furnace smelting.

The foregoing treatment of the ore material is usually accomplished byhaving resort to grates in the form of large, heavy cast iron sections.The grates in turn are usually supported on a rigid framework of castiron, usually a one-piece casting, and the assembled grate and supportare used as a pallet or conveyor. To this end, the framework or base forthe grates is sometimes provided with rollers, and a conveyor path ortrack is afforded for the rollers enabling the assembly to move into,through and out of the furnace. The conveyor path is sometimes ofendless form, being reversed at the opposite ends thereof, so that afterpassing through the furnace the grates and support therefor areinverted.

It has been found, however, that cracking and warpage of the grates isbecoming increasingly frequent, and in many instances the grates areactually burned out, especially as it has been found necessary in recentyears to use higher and higher temperatures in the furnaces. This,coupled with the relatively heavy nature of the grates and the supporttherefor, tending to introduce serious maintenance considerations, havepointed in recent years to the need for substantial improvements in thistype of furnace equipment, especiallysince it is recognized that infuture years temperatures in the furnaces are going to be even higher.

In view of the foregoing, it is an object of the present invention toreplace grates as heretofore used for the above purpose with a flexibleopen-mesh chain-type hearth consisting of articulated links. Thus,instead of a heavy cast iron grate having little resistance to thermalshock and stressing, the present invention utilizes a multiude ofindividual links each adapted to expand and contract individuallywhereby the possibility of Warpage and cracking is reduced to a minimum.Additionally, the links can be cast of a heat resistant alloy wherebythe life thereof is greatly enhanced and prolonged in comparison to theconventional grates. The links are spaced one from the other so that asignificant area of the pallet, from ten percent to twenty percent isopen, enabling contraction and expansion to occur freely and enablingthe hot atmosphere in the furnace to be readily accessible to the orematerial on the hearth. In the event that one particular link shouldperchance be thermally damaged, it is merely necessary to replace thatparticular link. This can be conveniently accomplished as will beexplained.

The rigid framework for supporting grates as menice thermal stressing inan ore treating furnace as the grates, and identical problems areencountered. Moreover, the combined weight of the grates and theframework necessitates the use of substantial and expensive elements inthe conveyor flight used to convey the assembly into, through and out ofthe furnace, especially where the conveyor flight is reversed on itself.Accordingly, another object of the present invention is to utlize withthe above mentioned chain-type hearth a support therefor consistingprimarily of a plurality of light-weight centrifugally cast tubes. Thesehave substantially less weight than the heretofore used rigid frameworkof cast iron, and additionally can be cast of a heat resistant alloy.The ends of the flexible chain-type hearth can be joined to the tubeswhereby the intermediate area of the hearth is loose and flexible.Therefore, in those instances where a reversing conveyor path is used,the intermediate area of the pallet is in effect jostled and flexed asit passes about the reversing end of the conveyor flight after leavingthe furnace, and this will have the effect of cleaning the hearth byshaking residual ore material therefrom. Additionally, the tubularconstruction of the support for the pallet achieves high strength withlow weight, and the capability of casting the tubes of heat resistantalloy imparts long life thereto.

Other and further objects of the present invention will be apparent fromthe following description and claims and are illustrated in theaccompanying drawings which, 'by way of illustration, show a preferredembodiment of the present invention and the principle thereof and whatis now considered to be the best mode contemplated for applying thatprinciple. Other embodiments of the invention embodying the same orequivalent principle may be used and structural changes may be made asdesired by those skilled in the art without departing from the presentinvention and the purview of the appended claims.

In the drawings:

Fig. 1 is a plan View of the pallet of the present in- Fig. 4 is a topplan view of one of the numerous links of the hearth;

Fig. 5 is a side elevation ofthe link shown in Fig. 4;

Fig. 6 is a top plan view of one of the side links for the hearth;

Fig. 7 is a side elevation of the link shown in Fig. 6;

Fig. 8 is a partial plan view of an enlarged scale of a portion of thehearth;

Fig. 9 is a perspective view of an intermediate link; and caljigs. 10and 11 are views of a repair link, reduced in s e. a

The present invention in one form is illustrated in Fig. 1 as embodiedin a pallet 20 which is adapted to be moved into and through a furnace.The pallet 20 includes a primary or base support 21 the details of whichwill be described hereinafter, and supported by the base 21 is aflexible, chain-type hearth 25, a fragment of Which is illustrated on anenlarged scale in Fig. 8. The hearth 25 is of general rectangularextent, and the front and'rear ends thereof are secured, in a manner tobe explained, to the front and :rear tubes 26 and 21included in the basesupport. The hearth 25 presents a 7 substantially planar upper surfaceas can be seen in tioued above is of course subjected to the same sortof Fig. '2, and the upper surface thus afforded is adapted tosupport,for firing in the furnace particles of;iron ore Y 3 or the like to besubjected to the hot atmosphere of the furnace.

In accordance withthe present invention, the base support 21 is ofrelatively light weight construction in comparison to what hasheretofore been aiforded in equipment of this general order. Asmentioned above, the support 21 includes at least a front and rear tube26 and 27, and in order that some appreciation may be had of the generaldimensions of the structure here involved itnnaybe pointed out that thetubes 26 and 27 in one embodiment of the invention are approximatelyfive .and one-half feet long with an outside diameter of approximatelyfive .and one-half inches. In the present instance, the .base member 2 1also includes an intermediate tube 30 which is adapted primarily toprevent sagging of the internal portion of the hearth 25. The tubes 26,27 and 30 are cast centrifugally of a heat resistant alloy so as toimpart to the base member 21 a relativelylong thermal life, and thehollow nature of the tubes achieves substantial strength with lowweight.

The arrangement of supporting tubes of the base member 21 which supportsthe hearth 25 is one of general rectangular extent, and in achievingthis configuration the ends of the tubes are connected to side plates aswill be described, and the side plates in turn, in one embodiment of theinvention, carry rollers so that the pallet unit 20 can be guided into,through, and out of'the furnace along a track. Thus, as shown in Figs. 1and 2,

relatively thick, sturdy left and right hand side plates 35 and 36 areafforded in the form of one-piece castings. The side plates'35 and 36have fiat inner faces 37, and left and right hand mounting plates 39 and40 are disposed against the flat inner faces of the side plates 35 and36. A plurality of mounting studs as 41 are extended through boredopenings in the side plates and have threaded inner ends 42, Fig. 2,which are threaded into corresponding tapped openings formed in theouter faces of the mounting plates 39 and 40; The studs 41 have threadedouter ends 43 which project outwardly of the outer sides of the endplates 35 and 36, and nuts 45 are threaded thereon to tightly clamp themounting plates to the side plates so as to become, in effect, a partthereof.

The mounting plates 39 and 40 are cast members and are cast with aplurality of hollow bosses 50 cor-responding in number and spacing tothe tubes. Thus, each of the mounting plates in the present instanceincludes three bosses 50. The ends of the tubes 26, 27 and 30 aretelescoped onto the bosses '50 so that the ends of the tubes abutshoulders 503, Fig. 2, on the mounting plates defining the base of eachboss 50. The opposite ends of each of the tubes 26, 27 and 30 are eachprovided with an annular chamfer, and this chamfer is filled with a buttweld W-l, Fig. 1, fused to the shoulders 508, thereby rigidly connectingthe tubes to the mounting plates included as parts of the side plates.Additionally, each tube at each end thereof is formed with upper andlower openings, and these openings, as shown in Fig. 2, are

filled with plug welds W-Z fused at corresponding points to the bosses50.

As shown in Fig. 2, each .side plate 35 and 36 is cast with a pair ofoutwardly projecting bearing blocks 60. An opening 61 is tor-med in each:bearing block 60, and a bearing bushing 62 is pressed therein forrotatably supporting a journal 65 of a flanged wheel or roller 66, therethus being four such 'wheels on the assembly.

Each of the side plates 35 and 36 is additionally formed with a verticalflange 70 which is disposed in a plane spaced outwardly of the plane ofthe corresponding flat inner face 37 of the related side plate. A lockpin 71 is mounted in each flange 70 substantially at the medial portionthereof. Such lock pin extends inwardly so as to be spaced above theopposite end portion of the intermediate tube 30, and serves to limitexcessive flexing of j mosphere. 75

2,955,812 i i r w 4 ly when the assembly is inverted, as will beappreciated from the description to follow.

The hearth 25 consists primarily of a multitude of individual links 75,Figs. 1 and 4, each cast as a onepiece part of heat resistant alloy.Referring to Figs. 4, 5 and 9, each link 75 includes a top plate 76 of ageneral rectangular configuration having a flat upper surface. Each link75 additionally is formed with a pair of generally U-shaped end collars77 and 78 which are of reduced dimension in comparison to the lateralwidth of the top plate 76. As shown in Figs. 5 and 9, the end collars 77and 78 aiford end openings 79 and 80, and the lower ends of the collars77 and 78 are joined by a bottom plate 82 having the same width as thecollars. The links 75 are reinforced by a relatively narrow verticallydisposed web portion 85 which is medially located between and joins theopposed faces of the plates 76 and 82. The ends of the web 85 arearcuate as will .be observed in Fig. 5 and cooperate with the endcollars to define the openings 79 and 80. As shown in Fig. 9, outwardlyprojecting lugs as 86 are formed on the edges of the bottom plate 82 ofthe links 75 so as to be coplanar therewith. The ends of the lugs 86, asshown in Fig. 4, are aligned with the outer edges of the top plate 76.

'All of the links 75 used for the hearth 25 are of identicalconstruction, and as shown in Figs. 1 and 8 are adapted to be arrangedin a side by side relation in transverse or lateral rows between theside plates of the pallet with the end collars of the links in each rowaligned to place the openings defined by the end collars in registry.The dimensions of the links is such that when so aligned in rows, theadjacent end collars as 77 of an adjacent pair of links as L1 and L-2,Fig. '8, in a particular row'are spaced'apart, this being primarily dueto the narrowed dimensions of the end collars in comparison to the top.plates 76. The spacing between the end collars thus afforded enablesthe opposite end collar 78 of a link L3 in the next adjacent row oflinks to be disposed therein so that the opening defined by the endcollar 78, Fig. 8, is in registry with the openings afforded by the .twospaced end collars 77, Fig. 8.

The ends of the links in adjacent intermediate rows of links that arethus interfitted in the manner shown in Fig. 8 are articulated, and thisis conveniently accomplished by pivotally associating theinterfittedends of the links as by elongated rods or pins 90, Fig. 1,passed through the registered openings in the interfitted ends of thelinks. The two'end rows ,of links are articulated to the support 21 in amannerto be explained."

The dimensions of the support 21 of course determined in relation to thetransverse span of the chain-type hearth, or alternatively, for a givenfurnace installation having a pre-determined track span, the links areaccordingly dimensioned in relation to the track span. In any event, itis advantageous to have the links in the various rows spaced one fromthe other to enable the hot atmosphere in the furnace rising upwardlybetween thespacedsupport tubes 26, 27, and 30 to gain access to materialto be fired that is carried on the substantially planar surface of thehearth afforded by the top plates 76 of the links 75. Accordingly, thetop plates 76 and the lugs 86 of the links 75 are so dimensioned thatwhen the collars 77 and '7 8 are in interfitted abutted relation asshown in Fig. 8, spaces S are established betweenthe adjacent side edgesof the top plates of adjacent links in a row. In like manner, the endsof adjacent lugs 86 are spaced the same distance S at the underside ofthe links, and since the bottom plates 82 are of reduced width incomparison to the top plates 76 there will be .quite extensive spacingbetween adjacent edges of adjacent bottom plates in the rows of'links.In this manner, the material to befired on the hearth is extensivelyexposed to the furnace at- In this connection, it may be pointed outthat I have found that the spacings established in the above manner atthe upper surface of the hearth is advantageously about seventeenpercent, but this can be conveniently varied depending on circumstancesbetween ten and twenty percent.

It will be recognized that the links in effect zigzag in a front to reardirection as viewed in Fig. 1 due to the particular manner ofinterfitting the links. Therefore, in order to, in effect, establish astraight edge at the two side extremities of the hearth for purposes ofproperly and neatly relating the hearth to its support, I provide sidelinks 100, Figs. 1, 6 and 7 which are used in alternative rows of links.As can be seen in Fig. l, five rows of links are used in the hearth ofthe particular embodiment illustrated, and therefore four such sidelinks 100 will be used, two each for the ends of the second and fourthrows of links. The side links can be viewed as a union of one link 75and half of another link 75. Thus, each side link 100 is provided withinner end collars 77A and 77B and a top plate 76A joined integrallythereto. Each side link 100 has what constitutes an inside section andan outside section. The outside section will be adjacent the side plateof the base support 21, and referring to Fig. 6 this outside section isafforded by forming the top plate 76A with an outside extension 76AE,and the extension 76AE is in turn formed with a pair of end collars 77AEand 77BE which are of half width in comparison to the end collars 77 and78. The spacing between adjacent end collars as 77A and 77AE correspondsto the width of an end collar of one of the links 75. Thus, as shown inFig. 8, the end collar 78 of an ordinary link L-4 is disposed betweenthe end collars 77A and 77AE of the side link 100, and the relation issuch that the same sort of spacing as S decribed above is established.

Referring to Figs. 1 and 3, a pair of generally L-shaped retainer bars100 and 101 having vertical flanges 105 and 106 are welded at the loweredges of the flanges to the end tubes 26 and 27 of the hearth support.The horizontal flanges 107 and 108 of the retainer bars are spaced abovethe upper surfaces of the tubes 26 and 27 and extend inwardly of thesupporting area. The retainer bars are identical in construction, andthe horizontal flange in each instance is formed with a plurality ofspaced apart horizontal teeth 110, Fig. 1. The spacing between the teeth110 corresponds to the width of the end collars 77 and 78 of the links75, whereby the end collars ofthe links 75 in the two end rows of links,Fig. 1, are adapted to be fitted into the spaces between the teeth 110of the retainer bars. As shown in Fig. 3, the teeth 110 have dependinglips 111 formed with beveled lower ends which are welded to points onthe upper surfaces of the tubes 26 and 27.

It was mentioned above that the rods 94 serve to articulate the severalrows of links comprising the hearth 25, and as shown in Fig. 2, the rods90 are accurately dimensioned so that the ends thereof abut shoulders120 formed on the side plates 35 and 36 between the flanges 70 and themounting faces 37. When the hearth 25 is laid in place, the bottomportions of the links 25 repose on upper surfaces of the tubes of thesupport, and the rods 90 at ends thereof are held in place by theshoulders 120 against endwise displacement.

The hearth 25 is articulated to the retainer bars 100 and 101 by meansof a pair of end rods 125, Figs. 1 and 3. The rods 125 are longer thanthe rods 90, and apertures are bored through the flanges 70 andshoulders 120 of the side plates 35 and 36, these apertures being inalignment with the openings in the end collars of the links 75 which arepositioned between the retainer teeth 110 of the retainer bars. Thus,the rods 125 are disposed between the vertical flanges and the lips 111of the retain bars as shown in Fig. 3. The ends of the rods 125 extendoutwardly of the outer faces of the flanges 70 of the side plates asshown in Fig. 2 and are retained against displacement by washers andcotter pins as shown.

Hence, it will be seen that while the rods 99 are loose,

in a manner of speaking, the rods 125 are fixed and serve in cooperationwith the teeth 110 of the retainer bars to hold the hearth to itssupport. By having the rods 90 loose, the hearth 25 is able to flex orshake, and hence when the assembly is inverted in those instances wherethe assembly is used in connection with an endless conveyor track,flexibility of the hearth enables the hearth to be self-cleaning. Thelock pins 71 prevent any undue sagging at the time of inversion, and therods 90 will not over-ride the shoulders 120 to such an extent as tocause a link to be lost.

In the event that perchance a link as 75 should be burned through, thehearth can be easily repaired by having resort to a repair link 75R,Figs. 10 and 11. The repair links 75R are exact duplicates of the links75 but are severed or split down the center of the end collars and theweb as by a band saw to afford upper and lower halves 75U and 75L, Fig.11, having split end collars. The lower plate 82 of the repair link 75Ris formed with a counter-sunk opening 130, Fig. 10, for the head of thebolt B, Fig. 11. Aligned opening 131 and 132 are formed in the two halfwebs 85A and 85B which are produced as a result of severing a link 75,and the bolt B is adapted to be positioned in the openings 131 and 132with the threaded end thereof projecting at the top plate of the repairlink for reception of a nut N.

When a repair link is to be used, the two halves thereof will beassembled complementally in the void space of the hearth with the splitend collars thereof embracing the portions of the two rods that happento have been exposed by the burned link to be replaced. The bolt B isthen inserted in place, and the nut N tightened to draw the two halvesof the repair link together.

It was mentioned that the relative width of the top plate and the endcollars of :a link 75 is what accounts for the spaces S which render theplanar surface afforded by the top plates of the assembled linkdiscontinues at regular spaced intervals to a predetermined percentage.That this discontinuous or space area, as distinguished from the solidsurface area of the top plates, is readily variable for differentcircumstances can be seen from the following analysis of the way inwhich each link is dimensioned. Thus, referring to Fig. 4, the open endcollars 77 and 78 of the link each have an identical width W. The topplate 76 is wider than each collar and has two projecting side portionseach of width /2WX. The combined width of the two side projections ofthe top plate, that is, W-2X, is less than the width W of either endcollar. Hence, when three links as L1, L-2, and L-3, Fig. 8, areassembled with the fore collar 78 of the link L-3 in one row of linksinterfitted between and engaged with the two spaced :aft collars 77 ofthe links L-1 and L-2 in the next row of links, the resultant space Sbetween the side edges of the top plates of the links L-2 and L 3 willbe equal to 2X. Accordingly, by varying the valve of X, the dimension ofS will be varied proportionally.

It will be seen from the foregoing that the furnace pallet of thepresent invention is one having a strong, lightweight support of openframe-work comprising spaced centrifugal cast tubes that areconveniently joined at their outer ends to afford a support of generalrectangular extent. The hearth for the pallet is flexible in nature andconsists of rows of articulated links of heatresistant alloy such aschrome-nickel steel. The two end rows of links are fastened to theoutermost two tubes of the support in an articulated fashion. Theordinary links in the several rows are generally cruciform in outlineand have top plates which when assembled afford a planar surface forsupporting the material to be fired. This planar surface is, however,discontinuous and open at regular spaced intervals, as by inter-relatingthe dimensions of the top plates and the end collars in the mannerdescribed. This enables the heat of the furnace rising upwardly betweenthe spaced tubes of the sup- 7 port to gain' access to the materialcarried by the hearth to be fired in the furnace. The tubes can be castof a similar heat resistant alloy, and hence both the tubes and therlinks are capable of withstanding severe thermalstressing for prolongedperiods of time without warping or burning out. In'the event that aparticular link should be burned out, this is easily replaced asexplained. In this connection, a particular advantage of the presentpallet is the fact that resort can be had to alloys of considerable lessdensity than the heretofore used cast iron constructions.

Hence, while I have illustrated and described a preferred embodiment ofmy invention, it is to be understood that this is capable of variationand modification, and I therefore do not wish to be limited to theprecise details set forth, but desire to avail myself of such changesand alterations as fall within the purview of the following claims.

I claim:

. 1. In a furnace pallet for conveying ore material and the like througha furnace to be fired, a substantially rigid base support of generallyrectangular extent including a set of spaced tubes cast centrifugasllyfrom a low density heat resistant alloy, side plates connected to theends of the tubes, rollers von the side plates, retainer bars secured tothe end tubes in said set and each including spaced teeth, and aflexible chain-'type'heflth secured at the ends thereof to said endtubes, said hearth at'least' in the area inwardly of the side platesconsisting primarily of identical individual cruciform links castfrom alow" density heat resistant alloy and each comprising a top plate and apair of end collars, the top pla'tes'of said links being substantiallycoplanar inthe), assembly and the end collars of the links being alignedtransversely in rows and each of less width than therelated top plate,transverse rods passed through the aligned end collars therebyarticulati'ng'the ends of the 'linksand imparting flexibility to thehearth as a unit, the and dollars and top plates of the links beingconfigured to aflord spacing between the side edges of the top platesofthe links in the respectiverows thereby enabling the furnace atmosphererising between the tubes of the base support togain access to materialon the hearth to be fired, the portion of the hearth between said pairof tubesbeing loose, retainer pins extending inwardly from the' sides ofthe pallet tooverlie marginal portions of the hearth and prevent undueflexing thereof, and the linkcbllars' cruciform links each comprising atop plate and a pair of end collars of reduced dimension in comparisonto the width of said plate, said end collars having openings therein,the top plates of said links being substantially coplanar and the endcollars of the links in eachrow being aligned transversely and spacedtransversely one from the other in one row'with' the collars of thelinks in'the next row disposed in such spaces to havethe openings in thecollars thereof aligned with the openings in the collars in said firstrow of links, transverse rods passed through the aligned openings of theend collars thereby articulating the ends of the links and impartingflexibility to the hearth as 'a unit, the collars and top plates of thelinks being configured to alford spacing between the sides of the linktop plates enabling the furnace atmosphere rising between the tubes ofthe base support to gain access to material on the hearth to be fired; atoothed retainer bar on each end tube, and the end collars of the twoend rows of links being articulated to said retainer bar's, said'hearthbeing flexible between said retainer bars. e

3'. In a furnace pallet for conveying ore material and the like througha furnace to be fired; a base support comprising a plurality of spacedtubes including two end' tubes, and a flexible-chain-type hearth, saidhearth consisting primarily of transverse rows of identical individualcruciform links each comprising a top plate and a'pairof end collars ofreduced dimension in comparison to the width of said plate, said endcollars having openings therein, the top plates of saidlinks beingsubstantially coplanar and the end collars of the links in each rowbeing aligned transversely and spaced transversely one from the other inone row with-the collars of the links in the next row disposed in such,spaces'to have the openings in the collars thereof aligned with theopenings in the collars in said first row of links, transverse rodspassed through the aligned openings of the end collars therebyarticulating the ends of-the links and imparting flexibility to thehearth as a unit, the collars and top plates of the links beingconfigured to aifordspacing between the sides of the link top platesenabling the furnace atmosphere rising between the tubes of the basesupport to gain access to material on the hearth to be fired, retainermeans on each end tube, and the end collars of the two end rows of linksbeing articulated to said retainer means, said hearth being flexiblebetween said retainer means.

References Cited in the the of this patent UNITED STATES PATENTS 878,085Parker et al. Feb.'4, 1908 890,552 Bibb June 9, 1908 1,583,085Meiklereid May 4, 1926 1,602,030 Lansing Oct. 5, 1926 1,888,348 Hegeleret a1. -Nov. 22, 1932 2,672,412 Burrow et al. Mar. 16, 1954 2,834,593Hudson May 13, 1958 um l

